The long-term goal of this program is to develop new models to study human age-onset cataract via lens cells generated from embryonic stem (ES) cells. These models employ patient-derived induced pluripotent stem (iPS) cells differentiated into lens cells to study lens-cell homeostasis under conditions known to induce human cataractogenesis. The immediate goal of this R21 application is to perform systematic exploratory studies to generate lens cells form human embryonic stem (ES) cells using defined cell culture conditions. Age-related cataract is a disease of the lens that is responsible for nearly half of blindness worldwide, and is expected to increase as a result of increased life expectancy in both developed and underdeveloped countries. Age-onset cataracts develop after the age of 40 as a result of the progressive breakdown of the lens microarchitecture. Age-onset cataract is a complex disease involving both genetic and environmental factors. Lens opacities are thought to originate from the cumulative damage of environmental insults on lens proteins and other structural components of the lens from UV-B exposure, low antioxidant intake, and cigarette smoking. A systemic approach to study human cataract is hampered both by the lack of appropriate animal models, and limited use of primary lens cell and organ cultures. We have now identified an experimental protocol to generate large quantities of lens cells progenitor cells differentiated from human ES cell line, H1. This proposal will (1) establish an optimized experimental protocol to generate a highly enriched population of lens progenitor cells from human ES cells, (2) will establish conditions to generate differentiated lentoid bodies followed by their characterization, and (3) will test these experimental conditions using a representative pool of six iPS cell lines. These data will lay foundation for generation of lens cells using iPS cells from distinct cataract patients. The patient-derived lens cells will be available at quantities sufficient for biochemical studies of specific antioxidant defensive mechanisms to identify those lens protective mechanisms that play key roles in cataractogenesis. By identifying molecular targets for drugs to exploit, this novel approach will inspire a rational search for drugs to reduce the effects of aging on the lens. Collectively, these exploratory studies will be used for R01 projects to model human cataract using genetically and phenotypically characterized biological materials. PUBLIC HEALTH RELEVANCE: This application is relevant to human health as lens cataract is a major cause of worldwide blindness. Age- related cataract develops at some time after 40 years of age as a result of progressive breakdown of the ocular lens structure. Current treatment for senile cataract generally consists of surgery that replaces the opaque lens with an artificial intraocular lens. Although the surgery is performed routinely in the US at a rate of 1.8-2 million patients per annum, it represents a major Medicare reimbursement category. It has been estimated by the National Eye Institute, NIH (Bethesda, MD) that a 10-year delay in the onset of cataracts, could decrease the number of surgeries needed by almost one half, thus significantly decreasing vision care costs.